Precisely that! But apart from the inability to predict table occupancy (for which you could theoretically come up with some ML solution), the other issue is that from a strict economic sense, having people occupy a table for 3 hours vs 1 hour while paying the same amount of money is a singificant opportunity cost to the business. In essence, from the perspective of the restaurant, people who are having a 3-hour meal and a long conversation are using a resource for which they're not paying, while other potentially paying customers are being turned away.
A nice side effect of the tipping culture in the US is that this inefficiency is eliminated. That's why I find it hard to believe that businesses will find it in their best interest to eliminate tips.
A nice side effect of the tipping culture in the US is that this inefficiency is eliminated. That's why I find it hard to believe that businesses will find it in their best interest to eliminate tips.